JP2004185477A - Optical storage medium array device and data transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for shortening a data transfer time in an optical disk array device having a plurality of optical storage media and a plurality of drives. <P>SOLUTION: In the optical disk array device, in which redundant data are stored during data writing, verification processing is not carried out in writing, or alternatively, verification processing is carried out only at previously registered intervals. The interval for performing verification processing is changed in compliance with a retry occurrence frequency in wiring and a recovery occurrence frequency in reading. Correspondence information between a storage position in the optical storage medium and whether writing is carried out after verification or not is stored, and consistency of a bit written without performing verification is checked. If the bit is not consistent, a request for rewriting of the data is notified to a host computer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for reducing a data transfer time in an optical storage medium array device having a plurality of built-in optical storage media.
[0002]
[Prior art]
2. Description of the Related Art An optical disk array device that stores a plurality of optical storage media such as rewritable DVDs (Digital Versatile Discs) and has a disk array configuration is used for data backup as an alternative to a magnetic disk.
[0003]
Here, an optical storage medium such as a rewritable DVD is a large-capacity, low-cost portable medium, but is known to have a relatively high error rate. Therefore, in order to increase the validity of the data with respect to the defect of the optical storage medium, it is general to perform a verifying process at the time of writing data.
[0004]
The verifying process is a process of reading the recorded data immediately after recording the data on the optical storage medium and comparing the read data with the original data to perform a check. For this reason, the data transfer speed in the case of writing data while performing the verifying process is about half that in the case of writing without performing the verifying process.
[0005]
On the other hand, the disk array configuration is a technology that allows a plurality of disk devices to operate in parallel, thereby enabling faster access than a single disk.
[0006]
If n disk devices are simply arranged, the failure rate is only n times worse. Therefore, generally, in a disk array configuration, RAID (Redundant Arrays of Inexpensive Disks) is employed as a technique for achieving both high speed and high reliability. The RAID realizes high-speed control by operating a plurality of disks in parallel, and achieves high reliability by contriving to increase data redundancy during storage.
[0007]
In a RAID, file data transferred from a host computer is divided into data blocks of an appropriate data length, the divided data is distributed and stored on a plurality of disks, and redundant data is written during writing. There is a configuration in which storage is simultaneously performed to improve disk failure reliability.
[0008]
Note that a data group divided for storage in a plurality of drives is hereinafter referred to as a data stripe.
[0009]
Thus, in RAID, even if a certain disk device fails, data of the failed disk can be restored from the other disks and the parity data. RAID realizes high-speed control by operating a plurality of disks in parallel, and also enhances reliability.
[0010]
Note that parity and in-disk error correction code ECC (Error Check Code) are known as redundant data used in RAID.
[0011]
As a disk array device using an optical storage medium, a device designed to increase the transfer speed is, for example, an optical disk library device disclosed in Patent Document 1. By providing a plurality of accessors, the disk exchange time is shortened in response to an access request to an optical storage medium, and the data transfer speed is increased.
[Patent Document 1] JP-A-11-45497
[Problems to be solved by the invention]
When a configuration in which redundant data is added to a data stripe is used, a time for processing for creating redundant data is required in addition to the verification processing, so that the data transfer speed is further reduced as compared with a case where only the verification processing is performed. .
[0012]
In the optical disk library device disclosed in Patent Document 1, the exchange of the optical storage medium is completed in a short time, so that the data transfer speed is increased to some extent. However, since the verifying process is still performed every time the writing is performed, the improvement of the transfer speed is not significant.
[0013]
As can be generally said to the data reliability assurance by the verifying process, the data reliability is guaranteed only by the verifying process only at the time of writing and then by the reading due to the deterioration of the optical storage medium that occurs thereafter. Failures cannot be dealt with.
[0014]
The present invention has been made in view of the above circumstances, and has as its object to provide a technique for shortening the data transfer time in an optical disk array device having a redundant configuration and an error correction function.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, when an optical disk array device to which data is written has a redundant configuration, the verifying process is not performed at all at the time of writing data, or the verifying process is performed at a preset frequency.
[0016]
When the verification process is performed at a preset frequency, the frequency is adjusted according to the result of the verification process.
[0017]
Also, when reading data, the quality of the stored data is checked, and the frequency of performing the verify process is adjusted according to the result.
[0018]
Furthermore, while not performing data write and read processing, the stored data is extracted without performing the verify processing, the consistency is checked using redundant data, and if inconsistency occurs, the reread processing is performed. Ask for.
[0019]
Specifically, the optical disk array device of the present invention is an optical disk array device having one or more optical storage media and one or more optical storage media drives for writing and reading data to and from the optical storage media. A redundant data calculating means for adding redundant data to the data in accordance with a predetermined instruction; and a verifying process for writing data to the optical storage medium when the redundant data calculating means adds redundant data. Verifying interval setting means for setting a verifying interval for performing the above, write control means for changing the verifying interval in accordance with the number of rewrite requests generated at the time of writing data to the optical storage medium, and the optical storage medium The read interval for changing the verify interval in accordance with the number of reread requests generated when reading data from And a control unit.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments to which the present invention is applied will be described with reference to the drawings.
[0021]
FIG. 1 is a system configuration diagram of the present embodiment.
[0022]
In the figure, 100 is a host computer, and 110 is an optical disk array device to which the present invention is applied. The optical disk array device 110 is connected to the host computer 100 via the host interface 140.
[0023]
The host computer 100 includes a transfer control unit 105 for transferring data to the optical disk array device 110.
[0024]
The optical disk array device 110 has a disk array configuration, and stores data transmitted from the transfer control unit 105 of the host computer 100 in its own optical storage medium.
[0025]
The optical disk array device 110 includes an optical disk array controller 120 and at least one optical storage library device 130 to 134. The optical disk array controller 120 and each of the optical storage library devices 130 to 134 are connected via drive interfaces 190 to 194, respectively. Connected.
[0026]
In addition, the optical storage library devices 130 to 134 include at least one drive 170 to 174 for writing data to the set optical storage medium and reading data from the set optical storage medium, and at least one optical storage medium 180. Is provided. In accordance with write and read instructions from the host computer 100, an optical storage medium 180 having a data area to be accessed is appropriately set in the drives 170 to 174, and data is written and read via the drives 170 to 174.
[0027]
Here, the optical disk array controller 120 generates a data stripe from data transferred from the host computer 100, and controls the transfer of the data stripe to the optical storage library devices 130 to 134.
[0028]
FIG. 2 is a functional configuration diagram of the optical disk array controller 120. As shown in the figure, the optical disk array controller 120 includes a host connection unit 121, a data storage unit 123, a redundant data operation unit 124, a verification process management unit 125, and storage device connection units 1220 to 1224.
[0029]
Here, the transfer from the optical disk array controller 120 to the optical disk library device is called data writing, and the transfer in the reverse direction is called data reading. In the following, the retry process refers to a process of writing data again when an error occurs when writing data while performing the verify process. The recovery processing refers to processing in which an error occurs when data is read and restoration is performed using redundant data.
[0030]
The host connection unit 121 receives a command from the host computer 100 via the host interface 140, and performs data transfer with the host computer 100.
[0031]
The storage device connection units 1220 to 1224 transmit commands to the drives 170 to 174 of the optical storage library devices 130 to 134 via the drive interfaces 190 to 194, and perform data transfer with the drives 170 to 174.
[0032]
When an error has occurred during data transfer and a recovery process or a retry process has been performed, the storage device connection units 1220 to 1224 notify the verification process management unit 125 of the recovery process or the retry process.
[0033]
The data storage unit 123 functions as a buffer between the optical storage library devices 130 to 134 and the host computer 100. The data storage unit 123 temporarily holds the transferred data, and transfers the data from the host computer 100 when there is a re-access request from the host computer 100. That is, it is used as a disk cache for increasing the data access speed.
[0034]
Also, it stores control information for managing the verification process received by the host connection unit 121 from the host computer 100, and the like.
[0035]
Here, the control information for managing the verifying process is information indicating whether the verifying process is performed or not, and information used to specify the frequency of the verifying process if the verifying process is performed. These are values such as a verification frequency, a retry limit, and a recovery limit that are used in each processing unit of a verification processing management unit 125 described later.
[0036]
In the present embodiment, these values are received from the host computer 100. However, for example, the values may be set as initial values when the optical disk array device 110 is shipped and stored in the data storage unit 123.
[0037]
When the optical disk array device 110 has a configuration in which redundant data is recorded on the optical storage medium 180, the redundant data calculation unit 124 generates redundant data at the time of writing, and transfers the generated redundant data to the storage device connection units 1220 to 1224. If an error occurs when reading data from the optical storage medium 180 stored in the optical storage library devices 130 to 134, the data is restored using the redundant data.
[0038]
Here, configuration information indicating whether or not the optical disk array device 110 has a configuration for recording redundant data is stored in advance in the data storage unit 123 as configuration information. The redundant data calculation unit 124 determines the above configuration by referring to this information.
[0039]
The verify processing management unit 125 monitors the frequency of retry processing at the time of a write error to the optical storage medium 180 and the frequency of recovery processing at the time of a read error, and changes the verify frequency by changing the interval at which the verify processing is performed. Is controlled. Also, the reliability of the stored data is checked as appropriate, and rewriting of data with low reliability is encouraged.
[0040]
FIG. 3 is a functional configuration diagram of the verification processing management unit 125. As shown in the figure, the verify processing management unit 125 includes a verify interval control unit 1251, a write control unit 1252, a read control unit 1253, a data consistency determination unit 1254, a verify frequency storage unit 1256, a retry A limit storage unit 1257, a verify information storage unit 1258, and a recovery limit storage unit 1259 are provided.
[0041]
The verify interval control unit 1251 performs initial setting of a reference value used for each processing. The host computer 100 stored in the data storage unit 123 determines whether the optical disk array device 110 is configured to add redundant data. Based on a request from the server, a predetermined reference value is stored in the verification frequency storage unit 1256, the retry limit storage unit 1257, and the recovery limit storage unit 1259.
[0042]
For example, when a request to perform verification at a predetermined interval is made from the host computer 100, a value designating the interval (hereinafter, referred to as a verification interval value) is stored in the data storage unit 123.
[0043]
Note that time or the number of times is stored as the verify interval value. When the time is stored, the write control unit 1252 described later controls to perform the write with the verify process and then to perform the verify process at the first write after the stored time has elapsed. When the number of times is stored, control is performed such that, after writing with the verifying process is performed, the verifying process is performed at the time of writing after the stored number of times of writing.
[0044]
The write control unit 1252 determines whether or not to perform a verify process using the reference value stored in the verify frequency storage unit 1256 when a data write request is issued from the host computer 100. In addition, at the time of writing after performing the verify processing, it is determined whether or not the retry processing has been performed, and the reference value of the verify frequency storage unit 1256 is changed according to the result.
[0045]
Note that the write control unit 1252 has a counter 12520 that counts the number of occurrences of various events that occur during the processing. FIG. 9 shows an example of the counter 12520. As shown in the figure, the counter 12520 counts the number of times the retry process was not performed consecutively, and counts the number of times the retry process has been performed, and the verify continuous number counter 12521 without retry. A retry counter 12522, a continuous retry counter 12523 that counts how many times the retry process has been continuously performed, and a write counter 1224 without the verify that counts the number of times of writing without performing the verify process are provided. .
[0046]
The write control unit 1252 adjusts the frequency of performing the verification process by comparing the values stored in the counters 12520 with the values stored in the retry limit storage unit 1257.
[0047]
The read control unit 1253 changes the reference value of the verification frequency storage unit 1256 depending on whether or not the recovery process has been performed at the time of a data read request from the host computer 100. The read control unit 1253 has a counter 12530 that counts the number of occurrences of various events that occur during processing. The counter 12530 includes a continuous number-of-recoveries counter 12531 for counting the number of times the read process has been performed without the recovery process continuously, and a recovery occurrence counter 12532 for counting the number of times recovery has occurred. FIG. 10 shows an example of the counter 12530.
[0048]
The read control unit 1253 adjusts the frequency of performing the verification process by comparing the value stored in the counter 12530 with the value stored in the recovery limit storage unit 1259.
[0049]
The data consistency determination unit 1254 extracts the data stripe and the corresponding redundant data from the optical storage medium 180 of the optical storage library devices 130 to 134 as appropriate, checks the data stripe, and determines whether or not the redundancy data is consistent.
[0050]
When an inconsistency has occurred, the data consistency determination unit 1254 notifies the host computer 100 of data writing again. In this case, the status information returned to the channel on the host side at the time of normal error detection is newly provided with rewrite notification information and identification information of the data in which inconsistency has occurred, and notification is made using this.
[0051]
On the host computer 100 side, the transfer control unit 105 detects the state information, prepares the corresponding data again, and requests the optical disk array device 110 to write again.
[0052]
The data consistency determination unit 1254 operates when a request to write or read data from the host computer 100 to the optical disk array device 110 is not made.
[0053]
The verify information storage unit 1258 is an area for recording whether or not a verify process has been performed at the time of data writing. FIG. 8 shows a format example of the verify information storage unit 1258.
[0054]
As shown in this figure, the verify information storage unit 1258 includes a medium identifier field 810 for storing the medium identifier of the optical storage medium 180 to which the data has been written by performing the verify processing, And a write time field 830 for storing information indicating the time at which the data was written.
[0055]
The verification information storage unit 1258 may be stored for each optical storage medium 180. When each of the optical storage media 180 holds the verification information, the medium identifier field 810 may not be provided.
[0056]
The verify frequency storage unit 1256 is an area for storing an interval value for performing a verify process at the time of writing. FIG. 13 shows a format example of the verify frequency storage unit 1256. As shown in the figure, the verification frequency storage unit 1256 includes a verification presence / absence information field 12561 for storing information indicating whether verification is performed, a specification information field 12562 for storing information indicating whether time is specified or the number of times specified, and A verification interval value field 12563 for storing an interval for performing the verification process in accordance with the specification stored in the specification information field 12562.
[0057]
The retry limit storage unit 1257 stores a reference value of various times related to the retry processing that occurred when the verify processing was performed. FIG. 11 shows a format example of the retry limit storage unit 1257. As shown in the figure, a retry limit storage unit 1257 stores a reference value indicating the number of times the verify process is continuously performed without the retry process, a verify continuous number of times without retry reference value field 12571, and a permitted value. A retry upper limit reference value field 12572 in which the number of retry processes to be performed is stored, and a continuous retry upper limit reference value field 12573 in which the allowable number of consecutive retry processes to be generated are stored.
[0058]
As shown in FIG. 12, the recovery limit storage unit 1259 includes a continuous number-of-recovery-times reference value field 12591 that stores a reference value of the number of times that the recovery process has not been continuously performed, which is a criterion for expanding the verification interval. And a recovery occurrence upper limit reference value field 12592 for storing an upper limit reference value of the total number of times recovery has occurred when reading data written without verification.
[0059]
The reference values stored in the retry limit storage unit 1257 and the recovery limit storage unit 1259 are specified by the host computer 100 and stored in the data storage unit 123. It is obtained from the storage unit 123 and written.
[0060]
The hardware configuration of the optical disk array controller 120 having the above functions includes, for example, as shown in FIG. 14, the CPU 200, the memory 210, the interface 220 with the host computer 100, and the optical storage library devices 130 to 134. It is composed of interfaces 230 to 234 and the like.
[0061]
The interface 220 with the host computer 100 and the interfaces 230 to 234 with the optical storage library devices 130 to 134 implement the host connection unit 121 and the storage device connection units 1220 to 1224, respectively.
[0062]
Further, the CPU 200 implements a redundant data calculation unit 124 and a verification processing management unit 125, and the memory 210 stores the storage units 1256 to 1259 of the data storage unit 123 and the verification processing management unit 125.
[0063]
FIG. 15 shows an example of a hardware configuration of the host computer 100. As shown in the figure, the host computer 100 includes a CPU 1100, a memory 1200, an interface 1300 with the optical disk array device 110, a display device 1400, and an input device 1500.
[0064]
The CPU 1100 realizes the function of the transfer control unit 105, the input device 1500 receives an input such as an instruction to give an instruction to the optical disk array device 110 from the host computer 100, and the display device 1400 transmits the instruction from the optical disk array device 110 to the host computer 100. Display notifications to.
[0065]
Hereinafter, the processing operation of the verification processing management unit 125 will be described.
[0066]
First, the verify interval control unit 1251 sets a reference value as an initial value in each of the storage units 1256 to 1259. Then, at the time of data writing, the writing control unit 1252 monitors the writing status, and changes the reference value stored in the verification frequency storage unit 1256 according to the frequency of retry processing. At the time of data reading, the reading control unit 1253 monitors the reading status, and changes the reference value stored in the verification frequency storage unit 1256 according to the frequency of occurrence of the recovery processing.
[0067]
Further, in addition to the time of writing and reading, the data consistency determination unit 1254 checks the consistency of the data stored in the optical storage library devices 130 to 134 using the redundant data, and Is requested to the host computer 100.
[0068]
The above-described operations of the respective units of the verifying process management unit 125 guarantee that data can be stored with high reliability stochastically / statistically without performing the verifying process for each write.
[0069]
Hereinafter, the processing operation of each unit will be described in detail. Hereinafter, a case where the number of times is recorded as the verify interval value will be described as an example.
[0070]
First, the processing procedure of the verify interval control unit 1251 will be described below.
[0071]
FIG. 4 shows a processing flow of the verify interval control unit 1251.
[0072]
The verify interval control unit 1251 first performs a process of initially clearing each storage unit and counter, and then sets a default value indicating that a verify process is performed every time in each field of the verify frequency storage unit 1256 at the time of writing. (Step 410).
[0073]
Then, it accesses the redundant data calculation section 124 to determine whether the optical disk array device 110 is configured to record redundant data on the optical storage medium 180, and receives the result (step 420).
[0074]
If it is determined in step 420 that redundant data is not recorded, the process ends. In this case, at the time of writing, a verify process is performed every time.
[0075]
On the other hand, if it is determined in step 420 that the configuration is for recording redundant data, information indicating that verification is not performed at the time of writing is set in the verification presence / absence information field 12561 of the verification frequency storage unit 1256 (step 430).
[0076]
Next, the data storage unit 123 is accessed to check whether a verify interval value is stored (step 440).
[0077]
If it is determined in step 440 that the verify interval value has not been stored, the process ends. In this case, the write process is performed without performing the verify process at all.
[0078]
On the other hand, if the verification interval value is stored in step 440, the verification interval value and the specification information indicating whether the time is specified or the number of times are specified are stored in the specification information field 12562 and the verification interval value field 12563 of the verification frequency storage unit 1256. (Step 450).
[0079]
When the optical disk array device 110 is configured to store redundant data, no verifying process is performed, or the verifying process is performed only at the time of predetermined writing according to the verify interval value set in step 450.
[0080]
Here, when the number of redundant data per data stripe used by the redundant data calculation unit 124 is two or more, that is, whether or not it is multiple parity is checked. Processing such as extending the set verify interval value may be performed (steps 460 and 470). This is because in the case of multiple parity, it is determined that the redundancy is high and the reliability is high.
[0081]
Next, the data storage unit 123 is accessed, and the upper limit reference value of the number of times the retry process is performed, the upper limit reference value of the number of times the retry process is continuously performed, and the verify process in which no retry occurs are continuously performed. The reference value of the number of times is obtained from the reference value and set in each field of the retry limit storage unit 1257 (step 480).
[0082]
Then, when reading data written without verifying, the upper limit reference value of the total number of times recovery has occurred and the reference value of the number of times recovery processing has not been continuously performed are taken out from the data storage unit 123 to obtain the recovery limit. It is set in each field of the storage unit 1259 (step 490).
As described above, the reference values at the time of writing and at the time of reading are set.
[0083]
Next, the process of the writing control unit 1252 for controlling data writing using the reference value set above will be described below.
[0084]
The write control unit 1252 determines whether or not to perform a verify process using the reference value of the verify frequency storage unit 1256 when a data write request is issued from the host computer 100, and determines whether or not the verify frequency storage unit 1256 matches the write result. And processing for changing the reference value.
[0085]
FIG. 5 shows a processing flow of the write control unit 1252.
[0086]
As shown in this drawing, the write control unit 1252 receives a data write request from the host computer 100, first accesses the verify presence / absence information field 12561 of the verify frequency storage unit 1256, and determines whether or not a verify process is performed ( Step 500). Here, when the information indicating that the verify process is not performed is stored, the write without the verify process is continued (step 535).
[0087]
In step 500, when the information indicating the presence of the verification process is stored, it is determined whether the request from the host computer 100 is the first write command (step 510).
[0088]
Here, the first write command is a write command accepted for the first time after the power is turned on. This is counted by a counter or the like in the write control unit, which is cleared every time the power is turned off.
[0089]
If it is determined that the command is the second or later command, it is checked whether the value stored in the non-verify write counter 12524 is larger than the verify interval value stored in the verify interval value field 12563 of the verify frequency storage unit 1256. (Step 520). In step 520, it is also possible to use the elapsed time from the previous verification instead of the number of times of writing. In this case, the elapsed time from the verify processing is stored in the write counter without verify 12524.
[0090]
If it is determined in step 520 that the verification interval value has not been exceeded, the storage device connection units 1220 to 1224 are instructed to write to the drives 170 to 174 of the optical storage library devices 130 to 134 without performing the verification process. At the same time, the non-verify write counter 12524 in the write control unit 1252 is incremented by 1 (step 535).
[0091]
If it is determined in step 520 that the number of times of writing is greater than the verify interval value stored in the verify interval value field 12563, the verification processing is performed and the writing is performed via the storage device connecting units 1220 to 1224. Instruct the drives 170 to 174 of 130 to 134 (step 530).
[0092]
At this time, the non-verify write counter 12524 is cleared.
[0093]
Next, when the data is written in step 530, an error is detected when the verify processing is performed, and it is determined whether or not a notification indicating that the retry processing has been performed is received from the storage device connection units 1220 to 1224 (step 540).
[0094]
In step 540, when the notification is not received, the continuous retry number counter 12523 is cleared, and the verification without retry increases the counter of the continuous number counter 12521 by one. Then, the verification without retry compares the value of the continuous number counter 12521 with the value in the continuous verification reference number field 12571 without retry of the retry limit storage unit 1257 (step 555).
[0095]
Then, in step 555, it is determined that the number of times that the verification process is continuously performed without performing the retry process exceeds the value stored in the non-retry verification continuous number of times reference value field 12571 of the retry limit storage unit 1257. Then, the verify interval value in the verify frequency storage unit 1256 is increased (step 565), the verify frequency is reduced, and the process proceeds to step 590 described later.
[0096]
In step 555, it is determined that the number of times that the verification process is continuously performed without performing the retry process is equal to or less than the value stored in the retry-without-retry-verification-continuous-times reference value field 12571 of the retry limit storage unit 1257. If so, the process proceeds directly to step 590.
[0097]
On the other hand, if it is determined in step 540 that retry processing has been performed, the retry-less verify continuous count counter 12521 is cleared, and the values of the retry count counter 12522 and the continuous retry count counter are increased by one. Then, the value of the retry number counter 12522 is compared with the value in the retry upper limit reference value field 12572 (step 550).
[0098]
If the value of the retry counter 12522 exceeds the retry upper limit reference value 12572 in step 550, that is, if the number of times of retry processing exceeds the value in the retry upper limit reference value field 12572, the verification frequency is stored. The verify interval value of the unit 1256 is reduced (step 560), the verify frequency at the time of writing is increased, and the process proceeds to step 570 described later.
[0099]
If the value of the retry number counter 12522 is equal to or smaller than the value in the retry upper limit reference value field 12572 in step 550, the process directly proceeds to step 570.
[0100]
Further, the number of times of continuous retries at the time of verification, that is, the value held by the continuous retry number counter 12523 is compared with the value in the continuous retry upper limit reference value field 12573 (step 570).
[0101]
In step 570, if the value held by the continuous retry number counter 12523 exceeds the value in the continuous retry upper limit reference value field 12573, the write data held by the data storage unit 123 is written again (step 580), which will be described later. Proceed to step 590.
[0102]
This is to increase the reliability of data recorded on the optical storage medium 180. Generally, when an error occurs during verification, another area is allocated and writing is repeated until the verification becomes normal. Also in this step, similarly, the reliability of the recorded data is improved by writing to another area. Here, depending on the frequency of occurrence of the above-mentioned rewrite instruction, it is possible to adopt a configuration in which a notification such as replacement of a medium or a drive is issued.
[0103]
In step 570, if the value held by the continuous retry number counter 12523 is equal to or smaller than the value in the continuous retry upper limit reference value field 12573, the process directly proceeds to step 590.
[0104]
Next, the identification information, the section identifier, and the write time of the optical storage medium 180 recorded by performing the verify processing are written in the medium identifier field 810, the section identifier field 820, and the write time field of the verify information storage unit 1258, respectively. 830 (step 590), and the process ends.
[0105]
As described above, when the optical disk array device 110 is configured to store redundant data at the same time, the write control unit 1252 performs writing by reducing the frequency of performing the verification process, and performs the verification in accordance with the frequency of occurrence of the retry process. It is possible to change the interval value.
[0106]
The processing operation of the writing control unit 1252 has been described above.
[0107]
Next, the process of the read control unit 1253 that controls the reading of data using the reference value set by the process of the verify interval control unit 1251 will be described below.
[0108]
The read control unit 1253 changes the reference value of the verify frequency storage unit 1256 depending on whether or not a recovery process has occurred at the time of a data read request from the host computer 100.
[0109]
FIG. 6 shows a processing flow of the reading control unit 1253.
[0110]
As shown in the figure, the read control unit 1253 receives a data read request from the host computer 100, and instructs the storage device connection units 1220 to 1224 to read data from the optical storage medium 180 (Step 610). . Then, it is determined whether or not a recovery process has occurred at this time (step 620).
[0111]
If it is determined in step 620 that the recovery processing has not been performed, the continuous count counter without recovery 12531 is incremented by 1, and the value is compared with the value in the continuous count reference value field 12591 without recovery (step 640).
[0112]
In step 640, if the value of the continuous number-of-no-recovery counter 12531 exceeds the value in the continuous number-of-recovery-numbers reference value field 12591, and if "verify" is set in the verify presence / absence information field 12561 of the verify frequency storage unit 1256, For example, the verify interval value in the verify interval value field 12563 is increased (step 650), and the verify frequency is reduced.
[0113]
Here, the reference value 12591 of the continuous count without recovery may be further increased by one.
[0114]
Here, in the case where the verification is not set in the verification presence / absence information field 12561, the verification interval value is not changed. This may be because writing is performed without performing any verifying process.
[0115]
In step 640, if the value of the continuous number without recovery counter 12531 is equal to or less than the value in the continuous number of times without recovery reference value field 12591, the process ends.
[0116]
On the other hand, if it is determined in step 620 that the recovery process has been performed, the value of the continuous number counter 12531 without recovery is cleared, and the verification information storage unit 1258 is searched to store the data on which the recovery process has been performed. It is checked whether the identifier and the partition of the medium 180 are stored (step 630).
[0117]
If the identifier and the partition are not stored in step 630, the data on which the recovery processing has occurred has been written without the verification processing at the time of writing.
[0118]
In this case, the value of the recovery occurrence counter 12532 is compared with the value in the recovery occurrence upper limit reference value field 12592 (step 660).
[0119]
In step 660, if the value of the recovery occurrence counter 12532 is equal to or greater than the value in the recovery occurrence upper limit reference value field 12592, and if the verification is set in the verification presence / absence information field 12561 of the verification frequency storage unit 1256, For example, the verify interval value in the verify frequency storage unit 1256 is reduced, and the verify frequency is increased (step 670).
[0120]
Here, in step 660, the value of the recovery occurrence counter 12532 is equal to or greater than the value in the recovery occurrence upper limit reference value field 12592, and no verification is set in the verification presence / absence information field 12561 of the verification frequency storage unit 1256. If so, in step 670, the setting without verification in the verification presence / absence information field 12561 is changed to the setting with verification. In step 410 of the initial setting of the processing flow of the verify interval control unit 1251, a default value indicating that the verify processing is performed every time is stored in the verify interval value field 12563, so that the verify processing is performed every time.
[0121]
Of course, in this case, what is used as the verify interval value is not limited to this. For example, a configuration may be used in which the value stored in the continuous counter without recovery 12531 is used. In this case, if there is a recovery, the procedure is changed so that the continuous number counter 12531 without recovery is cleared in step 670 instead of step 630.
[0122]
In step 630, if the identifier and the partition are stored, it is determined that the data on which the recovery processing has been performed has been subjected to the verification processing at the time of writing, and has been processed without changing the verification interval value. To end.
[0123]
If the value of the recovery occurrence counter 12532 is smaller than the value in the recovery occurrence upper limit reference value field 12592 in step 660, the process ends without changing the verify interval value in the verify interval value field 12563. .
[0124]
As described above, the read control unit 1253 can change the verify interval value according to the frequency of occurrence of the recovery process when reading data from the optical storage medium 180.
[0125]
The processing operation of the read processing unit 1253 has been described above.
[0126]
Next, the data stripe and the corresponding redundant data are extracted from the optical storage medium 180 of the optical storage library devices 130 to 134, and whether or not the data stripe is consistent is checked. The processing of 1254 will be described below.
[0127]
Note that the data consistency determination unit 1254 performs processing while the host computer 100 does not instruct the optical disk array device 110 to write or read.
[0128]
FIG. 7 shows a processing flow of the data consistency determination unit 1254.
[0129]
As shown in the figure, when a write or read request is not received from the host computer 100, the data consistency determination unit 1254 uses the drive groups 170 to 174 for the storage device connection units 1220 to 1224, It is instructed to read from the optical storage medium 180 the stripe data recorded in the section not stored in the verification information storage unit 1258 and the corresponding redundant data (step 710).
[0130]
Next, it is checked whether or not the bits of the read stripe data and the redundant data are consistent (step 720).
[0131]
If it is determined at step 720 that the bit of the stripe data is not consistent, the transfer control unit 105 of the host computer 100 transmits, via the host connection unit 121, the data of the optical storage medium 180 in which the stripe data is stored. Is again written (step 730).
[0132]
Of course, if it is determined in step 720 that no inconsistency has occurred, the processing ends.
[0133]
As described above, the data consistency determination unit 1254 determines the consistency of each of the data stripes written without verification, and if there is an inconsistency, notifies the host computer 100 of the rewriting of the data. Can be.
[0134]
Next, the processing in the transfer control unit 105 of the host computer 100 when the notification is received in step 730 will be described with reference to FIG.
[0135]
Upon receiving the status information that is the notification of the rewrite, it is determined whether or not the data designated to be rewritten exists in the memory based on the identification information of the inconsistent data included in the status information (step 1610). .
[0136]
If it is determined in step 1610 that the data exists in the memory, the data is rewritten (step 1670).
[0137]
If it is determined in step 1610 that the data is not stored in the memory, it is determined whether the data can be reproduced by the data reproduction processing program stored in the host computer 100 (step 1620).
[0138]
If it is determined in step 1620 that the data is possible, the data is reproduced (step 1660) and rewritten (step 1670).
[0139]
If it is determined that the data cannot be reproduced in step 1620, the identification information of the inconsistent data is displayed on the display device 1400 to obtain the information for reproducing the missing data, and information necessary for reproducing the data is input. (Step 1630).
[0140]
When input of information is received via input device 1500 (step 1640), it is determined whether the received information indicates that rewriting is unnecessary (step 1650).
[0141]
If it is determined in step 1650 that the instruction does not require rewriting, the process ends.
[0142]
In step 1650, if all the information for reproducing the data to be rewritten has been prepared, data reproduction processing is performed (step 1660), the data is rewritten (step 1670), and the processing is terminated.
[0143]
As described above, according to the present embodiment, when the optical disk array device 110 is configured to store redundant data, data is written without performing the verifying process each time. Writing can be performed at a higher speed than in.
[0144]
Further, the frequency of the verifying process can be changed according to the reliability of the data during the writing process while performing the writing. Similarly, at the time of reading, the frequency of performing the verify process can be changed according to the reliability of the data to be read.
[0145]
That is, various reference values for changing the verification frequency are set, the write control unit 1252 changes the interval of the verification process according to the reference values and the frequency of the retry process, and the read control unit 1253 performs the recovery process. Can be changed in accordance with the frequency of the verification process.
[0146]
In addition, other than at the time of writing and reading, the data consistency determination unit 1254 checks whether or not there is inconsistency in the data written without performing the verification processing. The host computer 100 is requested to write.
[0147]
As described above, according to the present embodiment, since redundant data is included, when data is written to a storage device having a configuration capable of correcting an error generated at the time of writing at the time of reading, the frequency of write verification is reduced. As a result, the writing time can be reduced.
[0148]
As described above, it is possible to provide the optical disk array device 110 capable of performing high-speed writing while suppressing reduction in reliability.
[0149]
In the above embodiment, the storage device in which the optical storage media has an array configuration has been described as an example, but the present invention is not limited to this. The present invention can be similarly applied as long as redundant data is stored at the same time.
[0150]
【The invention's effect】
In an optical disk array device including a plurality of optical storage media, the transfer time can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a system according to an embodiment to which the present invention is applied.
FIG. 2 is a functional configuration diagram of the optical disk array controller of the embodiment.
FIG. 3 is a functional configuration diagram of a verification processing management unit according to the embodiment.
FIG. 4 is a flowchart illustrating a process of a verify interval control unit according to the embodiment;
FIG. 5 is a flowchart illustrating processing of a writing control unit according to the embodiment;
FIG. 6 is a flowchart illustrating a process of a read control unit according to the embodiment.
FIG. 7 is a flowchart illustrating a process performed by a data consistency determination unit according to the embodiment;
FIG. 8 is a diagram illustrating an example of a format of a verify information storage unit according to the embodiment;
FIG. 9 is a diagram illustrating an example of a format of a counter in a write control unit according to the embodiment;
FIG. 10 is a diagram illustrating an example of a format of a counter in a read control unit according to the present embodiment.
FIG. 11 is a diagram illustrating an example of a format of a retry limit storage unit according to the present embodiment.
FIG. 12 is a diagram illustrating an example of a format of a recovery limit storage unit according to the present embodiment.
FIG. 13 is a diagram illustrating an example of a format of a verify frequency storage unit according to the embodiment.
FIG. 14 is a hardware configuration diagram of an optical disk array controller of the present embodiment.
FIG. 15 is a hardware configuration diagram of the host computer of the present embodiment.
FIG. 16 is a flowchart illustrating processing when the transfer control unit of the present embodiment receives a rewrite notification.
[Explanation of symbols]
100: host computer, 110: optical disk array device, 120: optical disk array controller, 130 to 134: optical storage library device, 170 to 174: drive, 180: optical storage medium, 125: verify processing management unit, 1251: verify interval control , 1252: write control unit, 1253: read control unit, 1254: data consistency determination unit

Claims (11)

An optical storage medium array device having at least one optical storage medium and at least one optical storage medium drive for writing and reading data to and from the optical storage medium,
Redundant data calculation means for adding redundant data to the data according to a predetermined instruction;
When redundant data is added in the redundant data calculating means, when writing data to the optical storage medium, a verify interval setting means for setting a verify interval for performing a verify process;
Write control means for changing the verify interval in accordance with the number of rewrite requests generated at the time of writing data to the optical storage medium;
Read control means for changing the verify interval in accordance with the number of re-read requests generated when reading data from the optical storage medium;
An optical storage medium array device comprising: The optical storage medium array device according to claim 1,
The optical storage medium array device according to claim 1, wherein the write control means extends the verify interval when the number of times of writing in which the rewrite request does not occur exceeds a predetermined number. The optical storage medium array device according to claim 1 or 2,
The optical storage medium array device according to claim 1, wherein the write control means narrows the verify interval when the number of times of writing in which the rewrite request has occurred exceeds a predetermined number. The optical storage medium array device according to claim 1, 2, or 3,
The writing control means instructs the writing means to perform writing again when the number of times of continuous writing of the rewriting request exceeds a predetermined number. Storage media array device. The optical storage medium array device according to claim 1, 2, 3, or 4,
The optical storage medium array device according to claim 1, wherein the read control means extends the verify interval when the number of times of read in which the reread request has not been continuously generated exceeds a predetermined number. The optical storage medium array device according to claim 1, 2, 3, 4, or 5,
When a verify process is performed at the time of writing data to the optical storage medium, a verification information storage unit that holds information indicating a position of the optical storage medium to which the data is written is further provided.
When the re-read request occurs, the read control unit determines whether or not a verify process has been performed at the time of writing to the read data based on information held in the verify information storage unit. The optical storage medium array device, wherein when it is determined that the processing is not performed, the verification interval is narrowed. The optical storage medium array device according to claim 6, wherein
According to the information stored in the verify information storage means, data that has not been subjected to a verify process at the time of writing is read, and the consistency is checked using the redundant data. An optical storage medium array device further comprising a data consistency determination unit for requesting the computer to write the data again. A data transfer method for transferring data to one or more optical storage media via one or more optical storage media drives,
A redundant data calculation step of adding redundant data according to a predetermined instruction when writing data to the optical storage medium;
When writing data to the optical storage medium, data is written to the optical storage medium at a predetermined interval while performing a verifying process, and the interval is changed according to the number of rewrite requests generated during the verifying process. When reading data from the optical storage medium, a verify interval changing step of changing the interval according to the number of reread requests that have occurred,
A data transfer method comprising: The data transfer method according to claim 8, wherein
When writing data to the optical storage medium, a verify recording step of recording whether or not the verify processing has been performed;
Based on the data recorded in the verify recording step, data that has not been subjected to a verifying process when data is written is extracted and the consistency is checked using the redundant data. Requesting the computer that is the transfer source of the data to issue an instruction to write the data again. A computer mounted on an optical storage medium array device having at least one optical storage medium and at least one optical storage medium drive for writing and reading data to and from the optical storage medium;
Redundant data calculation means for adding redundant data to the data according to a predetermined instruction;
When redundant data is added in the redundant data calculating means, when writing data to the optical storage medium, a verify interval setting means for setting a verify interval for performing a verify process;
Write control means for changing the verify interval in accordance with the number of rewrite requests generated at the time of writing data to the optical storage medium;
Read control means for changing the verify interval in accordance with the number of re-read requests generated when reading data from the optical storage medium;
Program to function as The optical storage medium array device according to claim 1,
The optical storage medium array device, wherein when the redundant data is added by the redundant data calculation means, the verify interval setting means performs setting so as not to perform a verification process when writing data to the optical storage medium. .

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